This proposal describes a 3-year project by the American Psychiatric Institute for Research and Education to use medical informatics principles to enhance the development and dissemination of evidence-based clinical practice guidelines for the treatment of patients with major depressive disorder, an illness with significant public health consequences. Clinical practice guidelines developed and published by many medical specialty organizations, synthesize available evidence and recommend specific treatments or practices, with the ultimate goal of improving patient outcomes and quality of care. Clinicians may not use guidelines, however, if the contents are not up-to-date or if the guidelines are not easy to access and understand at the point of care within a busy clinical environment. Both problems are liabilities of guidelines developed using a traditional narrative information structure. Under this proposal, published research studies on the treatment of depression will be collected, evaluated, and organized within a relational database. Within the same database, modules of practice recommendations will next be developed each focused on a clinical question with potential impact on quality. Modules will also provide discussion and links to the supporting evidence. The clinical information needs of psychiatrists who treat patients with major depressive disorder will be evaluated using an established practice research network. Results will inform the design of a database-driven Web-based system with enhanced search functionality for publication of the guideline modules. The usability of the system will undergo iterative user testing and improvement. If successful, this development approach and the publication technology may be implemented for guidelines on other psychiatric disorders and may be replicated by other guideline developers, enhancing the translation of medical research into clinical practice.